Abstract: To clarify the development stages and characteristics of China′s major coastal ports since its accession to the WTO, a quantitative study is conducted based on the monthly container throughput data of seven major coastal ports from 2002 to 2023. Multivariate change point analysis is introduced to objectively reflect the stage characteristics of port development, and the Chow test is used to verify the reliability of the quantitative research results. The study shows that the major coastal ports in China can be divided into six development stages over the 22-year research period. By combining the characteristics of port container throughput growth in different stages and considering key events such as China′s accession to the WTO at the end of 2001, the outbreak of the global financial crisis in 2008, and the spread of COVID-19 in 2020, the six stages are identified as: rapid growth period（2002～2005）, fluctuating development period（2006～2010）, recovery growth period（2011～2013）, stable platform period（2014～2017）, development differentiation period（2018～2020）, and resilient growth period（2021～2023）. Each development stage exhibits distinct characteristics, closely related to the economic and trade conditions of China and the world during the respective periods.